If You Compared the Diameter of the Earth, Which Is

Multiple Choice

If you compared the diameter of the Earth, which is 13,000 km, to 1 second, then what unit of time would be equivalent to the size of the Milky Way, whose diameter is 10²¹ m, and what significant milestone would this time correspond to in our evolution?

A) 2 million years, the length of time humans have existed on Earth
B) 30,000 years, the length of time humans have lived in North America
C) 400 years, the length of time humans have been exploring the skies with telescopes
D) 4 billion years, the age of the Solar System
E) 14 billion years, the age of the universe